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Glossary of Garage Door and Garage Door Opener Terms

Astragal – Weather-stripping added to bottom section of the door to seal the opening.

Back Hangs – Vertical supports for the horizontal track, cross-braced to prevent lateral movement and track spread.

Backroom – The required clearance from the face of the header to any obstruction to the rear of the horizontal track.

Bead – A metal, vinyl or rubber strip used to secure glass around the periphery of a pane.

Bottom Bracket – A structural support located on the bottom section of the door which provides for attachment of the lifting cables on sectional doors.

Bracket Mounted Track – A method of fastening vertical track to a doorjamb using angle brackets.

Bumpers – A leaf spring installed at the end of the horizontal track. Acts as a cushion and stop on full vertical manually operated doors

Cable Drums – Grooved drums on the torsion spring shaft that lifting cables wind around when door is opened. Designed to allow cable to be accumulated or dispensed in an orderly manner and to prevent lapping or cable chafing.

Cable Safety Device – A safety bottom fixture specifically designed to prevent a door from falling in the event of cable breakage.

Cable Sleeve – A manufactured device used to form a loop of cable, size of which is determined by the cable diameter.

Cable Stop – A swaged fitting at the end of the cable to prevent slippage through a slot in a drum.

Cables – Multi-strand wire used to attach the door, via bottom brackets, to the counterbalance mechanism.

Center Hinge – Flat hinge located on all intermediate stiles to allow for door section to turn the track radius as the door opens.

Center Lift Cable – Additional cable assembly, which is secured to the outside of the door and points toward the center of the door. Used to provide extra lifting support for extremely wide or heavy doors.

Center Stile – Vertical members of a door section which provide structural rigidity and location for center hinge attachment.

Center Support Bearing – Bearing and mounting plate installed at approximately half the door width above the door which acts as a support for the spring shaft. Can be mounted in various locations, not necessarily in center, depending on size of springs.

Chain Hoist – Adds mechanical advantage to manually operated doors. Couples to one end of the solid torsion shaft.

Clearances – The amount of side room, headroom, and backroom required to properly install a sectional door.

Coupling – Adjustable cast iron connector in two halves for torsion solid shafts on wide doors. Eases installation and allows adjustment in cable lengths so doors will operate smoothly without cocking.

Curtain – The part of the sheet door that actually rolls up and down or slides side to side. Manufactured of corrugated sheets seamed together.

Cycle – One complete cycle of a door begins with the door in the closed position. The door is then moved to the open position and back to the closed position again. Note: Torsion spring operated doors with higher-than-normal cycle life requirements may be specified with 25,000, 50,000, or 100,000 cycle springs.

Dead Load – A load without movement.

Door Frame – The frame into which the door fits, consisting of two upright members called doorjambs, and a door header.

Door Size – Always listed with width first and height second: For instance 8′ 6″ wide by 7′ 3″ high.

Drums – Circular stamped metal parts attached at various locations along the tubular shaft that allows the sheet door curtain to coil up when the door is opened.

Duplex Spring – A combination of two torsion springs of different diameters telescoped within common spring cones.

End Stiles – A vertical piece located at each end of a door section that provides for attachment of end hinges.

Escutcheon – A plate surrounding the lock mechanism, acting as a bearing surface for the lock shaft; one of the parts of a lock set, usually held in place by small screws.

Exhaust Ports – Openings put in the bottom section of a door for release of carbon monoxide fumes when tubed from an automobile exhaust system.

Extension Springs – Counterbalance springs which provide lifting force by stretching. Commonly called stretch springs. Extension springs are mounted to each of the rear track hangers. They are attached to a pulley at the other end of the spring.

Exterior Lock – Keyed lock which can be operated on exterior of the door.

Flag Bracket – L-shaped bracket used to facilitate the union between vertical and horizontal tracks.

Flush Design – Refers to door sections unbroken by roll-formed ribs. The face of the complete door presents an even surface.

Front-Mounted Low Headroom – Low headroom hardware where springs mount on torsion shaft above opening.

Full Vertical Track Assembly – An assembly made up of a piece of vertical track and a piece of continuous angle or jamb brackets which is used to secure the track to the jamb.

Full Vision Section – A totally glazed section with various types of glass or clear plastic. The section is formed of aluminum extrusions that combine with steel sections above and below

Galvanizing – Zinc coating to protect steel against corrosion.

Glazed Glass – Section windows or lites in place of the steel or aluminum panel.

Head Plate – Structural bracket used to secure vertical and horizontal track, as well as counterbalance systems.

Headroom – A measurement from the top of the door opening upward to the lowest building obstruction on the inside of the header wall. Use this measurement for vertical clearance all the way back to the end of the horizontal track.

High Cycle Springs – Special counterbalance springs with increased life cycle capability for high usage doors.

Hinges – Found on the end stiles and center stiles at the meeting rails, they make the independent sections act as a complete door. They join the sections together with bolts or screws.  Additionally, they allow the sections to break, independent of each other, as the door travels.

Horizontal Track – An assembly usually made up of a section of track and reinforced with an angle that is used to both guide and support the door in the horizontal position. Furnished with an integral section of curved track.

Incline – Slope or slant. To follow roof pitch.

Inclined Track – Tapered vertical track and a graduated height of edge hinges which assure a weather tight fit between door and jamb.

Inside Lock – A spring loaded, sliding deadbolt.  Lock is operable only from interior of the door.

Insulated Glass – Two pieces of glass spaced approximately 1/4″ (12.7 mm) apart and hermetically sealed to form a single-glazed unit with an air space between. Heat transmission through this type of glass may be as low as half that of non-insulated glass.

Insulation – Material that has the ability to reduce heat or cold transmission.

Additional Terms Associated with Insulation:
– Amount of heat necessary to raise the temperature of one pound of water one degree Fahrenheit.
K-Value – Laboratory determined value of thermal conductance of a material.
R-Value – Ability of a material to retard the transmission of heat. Higher R-value= better insulating performance.
U-Value – Amount of heat, in BTU, is transmitted through one square foot of material (the door) in one hour at a temperature difference of 1° F from one side to the other. The lower the U-value, the better the insulating material.

Jamb Seal – Weather-stripping attached to the door jamb to provide a seal along the jambs.

Jambs – The upright framing on each side of the door opening.

Lift Clearance – Refers to track hardware that causes the door to rise vertically some distance before it levels out into a horizontal position.

Lift-Handle – Located on the bottom section of the door, assists in manually lifting the sectional door.

Lites – Frames glazed with glass or clear plastic. May be double glazed for insulation value.

Low Headroom – Track hardware accessories to provide for door installation with minimum headroom conditions.

Master Keying – Arrangements whereby cylinder locks, although fitted with different keyed cylinders, can be opened or locked by means of one key.

Meeting Rail – The top or bottom horizontal rail in any section that meets and joins with an adjacent door section in horizontal rail.

Mounting Plates – Flat steel or wood members placed on the wall to accommodate spring support, spring shaft bearings, chain hoists and mountings for operators.

Movable Center Post – A lightweight extruded aluminum post/track assembly, which substitutes for the jamb between two adjacent doors and can be released and carried from the opening.

Mullion – A slender dividing bar between two doors. Usually designed to carry horizontal (wind) load but not vertical load.

Muntin – A bar member supporting and separating panes of glass within a sash or door.

Opening Size – Frequently called the finished opening. Dimensions are taken between masonry or wood walls or between steel jambs.

Opening Width – Distance between jambs of the door opening.

Outside Hook-up – Bottom fixture with an arm that bends around vertical track to receive lifting cables.

Padding – Wood framing at jambs and header to which door track is mounted.

Pane – The area between vertical stiles in a door section.

Pass Door – It is a small swing door built into the larger upward acting door so that people can walk in and out without opening the large door. Cannot be used as a legal exit.

Pedestrian Door – Access door adjacent to the upward acting doors. Avoids the use of a sectional door as a legal egress.

Perimeter Seal – Complete weather-stripping package for sectional doors, consisting of astragral, jamb seal and header seal.

Perimeter Wear strip – Vinyl or felt attached to corrugated sheet door curtain to prevent rubbing. Located at the ends or drum locations.

Rabbeted Joint – Formed by fitting together rails with grooves cut out of the opposing edges to permit overlapping weather tight meeting of sections.

Radius – The curved portion of the track, which allows the door to move from vertical to horizontal (and vice versa). The curve is measured in inches, thus determining headroom requirements.

Rain Stop – A step at the edge of the garage floor, approximately 1 (25.4 mm) higher than the outside finish. The door sits between the two.

Rear Track Hangers – Often constructed of punched angle iron, laterally braced, these hangers attach the end of the horizontal track to the garage ceiling.

Removable Post – Designed to allow the use of two or more doors in a single opening with center posts that can be removed when doors are in the up position. Especially desirable where small openings are required normally, but occasionally the entire clear opening is necessary.

Reverse Angle Mounting – An exceptionally sturdy method of track mounting used on all steel jambs and wood jambs at the architect’s direction.

Roller Assembly – The combination of a wheel and axle that is used to guide a door through the track system, either 2″ (50.8 mm) or 3″ (76.2 mm) diameter, depending on track size

Rollers – Steel, ball-bearing wheels that allow sections to roll freely along door tracks.

Safety Spring Containment – An extra cable used with extension springs to prevent pieces of the spring from causing damage or injury in the event the spring breaks. The cable is threaded through the center of the spring and is secured on both ends of the horizontal track.

Sectional Joint Meeting Rail Seal – A weather-strip integral with the section at the joints between door sections.

Sectional Type Doors – Doors made of two or more horizontal sections hinged together to provide a door large enough to close the entire opening.

Shaft Bearings – Type of bearing that adequately supports the radial forces dictated by the weight of the counterbalance assembly and door weight, and the lateral forces exerted.

Sheave – A pulley with integral ball bearings designed to handle a cable and used to control the movements of the cables employed in the door counterbalance system.

Shiplap Joint – The configuration of the meeting rails. When closed, the shiplap prevents rain, wind, and light from infiltrating the door between the door sections.

Sideroom – A horizontal measurement from each side of the door opening outward along the wall to the nearest obstruction within the building.

Spring Anchor Plates – Designed to transmit torque from the stationary end of a torsion spring to the building structure and, at the same time, support the weight of the torsion shaft in a level attitude. The anchor plate is able to withstand the lateral forces exerted by a torsion spring.

Spring Assembly – Hardware used to make up the door counterbalance assembly.

Spring Bumper – Small spring-cushioning bumper attached to the horizontal track, which stops the door at the full open position.

Spring Fittings – The sleeves or cones, which are used to affix the torsion springs to the torsion shaft. One piece is a stationary sleeve and the second piece is an adjusting cone or winding sleeve.

Steel Jambs – Door framing made from either channel or angle iron.

Stop Molding – Serves to seal the perimeter of the door against weather and light infiltration.

Stops – Bars or brackets mounted at top of guides to prevent bottom bar from traveling out of the guides when the sheet door curtain is fully raised.

Straight Incline Track – Vertical track assembly that extends from floor to twice the height of the opening without break-away feature.

Struts – L-shaped metal reinforcement members attached horizontally to the inside of the door section to add strength and rigidity. Struts are necessary on wide heavy doors to help prevent sagging and bowing and to provide additional reinforcement to comply with the required windloading.

Tempered Glass – Glass that has been reheated to just below the melting point and suddenly cooled. When shattered it breaks into small pieces.

Tongue-and-Groove – The configuration of the meeting rails that differs from shiplap in having matching channel groove and protrusion on the longitudinal edges of the abutting meeting rails for wind and weather protection.

Top Fixture – Adjustable brackets that carry track rollers mounted on the top corners of the top section of the door.

Top Header Seal – Flat weather strip fastened along the full width of top door section as a seal along the header.

Top Rail – The horizontal rail forming the top horizontal member of a door as distinguished from the meeting rails and bottom rail.

Top Seal – Weather stripping which fastens to the top of the door to provide a seal along the top of the opening.

Torque – The turning effect of a tangential force acting at a distance from the axis of rotation or twist; torsion springs apply such effect to spring shafts.

Torsion Shaft – The shaft of a torsion spring assembly, which transmits lifting force of the torsion springs to cable drums and lifting cables.

Torsion Spring Counterbalance Assembly – Designed and constructed to provide a safe and durable conversion of spring torque to lifting force by balancing the weight of a sectional overhead type door.

Torsion Springs – Mounts above the door opening. The springs are manually wound, or charged, then set to a shaft which runs through the spring. The spring turns the shaft, which raises or lowers the door via the cables winding on drums.

Track – Provide a guide for the roller wheels. The vertical track is mounted to the jambs with brackets on each side of the door opening. The horizontal track contains a curved end called the radius. In the closed position, the door is resting in the vertical track. In the open position, the door is suspended from the horizontal track. Sectional door track usually consists of 4 pieces: 2 vertical pieces and 2 horizontal pieces.

Trajectory – The arc of travel, or sweep of the top section, as the door is raised from closed to open position, important in planning the location of pipes, light fixtures.

Vertical Lift – A hardware design that allows a sectional door to open vertically along the wall above the door opening without turning back inside the building.

Wicket Door – Hollow-metal pedestrian door installed adjacent to the sheet door sharing the same building opening.

Winding Bars – Used by installers to set initial tension on torsion springs at the winding cones.

Winding Cone – Part that fits into a torsion spring, permitting winding of the torsion spring and tension adjustment.

Windload – The lateral force that the wind exerts upon a door as it stands in a closed position.

Wire Glass – Polished or rough glass, 1/4″ (6.35 mm) thick. Wire mesh is embedded within the glass so that the glass will not shatter when broken.

Wood Jamb Mounted – Regular method of mounting vertical track to wood jambs.

Wood Jambs – Upright piece forming the side of the door opening and is made of wood